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Upcoming Seminar/Colloqium


Study on Carbonaceous Aerosols over the Central Himalayas

Speaker : Priyanka Srivastava
Affiliation : ARIES
Date & Time :
Venue : Auditorium and zoom
Abstract :

In this era of rapid urbanisation and industrialisation, large dependence  on  carbon-based  fuel  has  led  to  a  substantial  increase  in  the  concentrations of carbonaceous aerosols (organic carbon-OC and black carbon-BC) which are emitted from their incomplete combustion.  These aerosols  are  important  due  to  their  direct adverse effects on health, radiation budget and their indirect effect in altering cloud properties, thus acting as strong short term climate forcers.  However,  assessment  of  the  overall  impact  of  these  aerosols  is  a challenging task because of the large spatial and temporal variations, types of mixing states and dynamic atmospheric processes. Despite  the  scientific  attention  on  this,  systematic  and  high-resolution  observations  of carbonaceous  aerosols  are  still  very  limited  in  South  Asia.  Such  measurements  are  almost inexistent in the Himalayan region, which has a complex topography and lies in close proximity to polluted regions like the Indo-Gangetic Plain (IGP). 
Underlying the aforesaid issues, I will present in this talk, my PhD thesis work from the long term online and offline observations of OC, BC, CO, TSPM along with  absorption cross-section from a high-altitude location in the Central Himalayas (ARIES, Nainital). I will first introduce  carbonaceous  aerosols, the challenges in their study and the importance of this work to overcome these challenges. Later, I will explain the in situ instruments, satellites and models used in the work for their characterisation. Then I will chapter wise present the results, discussing about their temporal variations, factors governing their diurnal and seasonal concentrations, importance of site, wavelength and month specific mass absorption cross-section estimated for the first time over the region, quantification of the sources of these aerosols over this region, novel methods employed for their source characterisation, impact of fossil fuel and biomass emissions, impact of long range transport, the underlying concentration trend and their impact on regional radiative forcing.

About Speaker :

Priyanka Srivastava is a PhD student at ARIES. This is her pre-PhD thesis submission seminar.